1. Field of the Invention
The present invention relates to compositions and methods for protecting metallic substrates from corrosion, and particularly to a method of applying a polyelectrolyte multilayer film for corrosion control, and to metallic substrates having a polyelectrolyte multilayer film applied according to the method.
2. Description of the Related Art
Metal components are often used in environments in which the components are subject to corrosion from exposure to the environment, harsh chemicals, etc. A variety of coatings have been developed for protecting metals from corrosion.
One such coating that has been developed in recent years is a polyelectrolyte multilayer (PEMU) film coating, as described in U.S. Patent Publication No. 2004/0265603 (the '603 publication), published Dec. 30, 2004 on behalf of inventor J. B. Schlenoff, which is hereby incorporated by reference in its entirety. The '603 publication describes the application of PEMU films to a stainless steel substrate. While application to such a substrate is effective, nevertheless, a problem arises in attempting to apply a PEMU film to other metallic substrates, such as mild or carbon steel substrates. The PEMU oxidize the mild or carbon steel substrates and lead to reddish, non-adherent films upon immersing the substrate in polyelectrolyte solutions for application of the coating.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, a method of applying a polyelectrolyte multilayer film for corrosion control solving the aforementioned problems is desired.